For an olive-sided flycatcher, migration could be a marathon. A few of the soot-colored songbirds journey greater than 15,000 miles a 12 months, winging their approach from South America to Alaska after which again once more. It’s a dizzyingly lengthy journey for a chook that weighs simply over an oz..
“Alaska populations of olive-sided flycatchers are simply on this razor-thin margin of what’s biologically attainable,” stated Julie Hagelin, a wildlife analysis biologist on the Alaska Division of Fish and Recreation and a senior analysis scientist on the College of Alaska Fairbanks.
To outlive the lengthy journey, the birds want secure locations to relaxation and refuel. However the places of those “little utopias” have been a thriller, Dr. Hagelin stated. So in 2013, she and her colleagues got down to unravel it by monitoring the birds. They hoped that figuring out the essential stopover websites may present clues about why olive-sided flycatcher populations have been declining and what is perhaps wanted to save lots of them, together with the place specialists ought to goal their conservation efforts.
The analysis proved to be tougher than that they had bargained for. Olive-sided flycatchers typically breed in buggy bogs. They perch on the tops of timber. And they’re elusive, sparse on the panorama and troublesome to catch. “After the primary 12 months of combating this venture, it turned actually, actually clear why no one of their proper thoughts would need to try to examine this chook,” Dr. Hagelin stated.
Right here’s what it took for scientists to get the info:
Make a lure
Olive-sided flycatchers could be extremely delicate to incursions into their territory, so the scientists lured the birds with pretend avian rivals. They purchased picket chook decoys on eBay, after which painted white patches on the flanks to copy the flash of white feathers that males typically present after they’re agitated. “It’s form of a protracted distance sign of ‘Maintain away’ or ‘That is my spot,’” Dr. Hagelin stated.
Catch a flycatcher
The researchers connected the decoys to small timber or tied them to massive sticks that have been positioned upright within the tender floor. They strung up advantageous mist nests and performed flycatcher calls from audio system hidden within the bushes beneath the decoy. The scientists hoped that if an actual flycatcher was within the space, it might fly on the picket interloper and wind up of their nets. Some birds did simply that, responding shortly to the decoy. However generally it might take hours to catch only one flycatcher. “Perhaps two, if we have been fortunate,” Dr. Hagelin stated.
Connect a tag
The researchers used clear plastic wire — designed for making beaded jewellery — to style tiny flycatcher harnesses, every bearing a geolocator tag. As soon as that they had a chook in hand, they slipped the loops of the harness over its legs, positioning the tag towards its decrease again.
When the birds flew south for the winter, the geolocator tags usually recorded the sunshine ranges and the time, permitting the scientists to estimate every chook’s approximate latitude and longitude. In later years of the examine, they transitioned to utilizing GPS tags, which may present extra exact location information.
Do it once more a 12 months later
To obtain the info, the researchers needed to recapture the identical birds the following summer season. “Recovering this info added to my grey hairs,” Dr. Hagelin stated. The second time round, the birds have been warier and fewer conscious of the scientists’ trickery, so the researchers spent hours watching flycatcher nests.
“You can begin to see patterns like places or instructions that the birds are inclined to exit or enter the nest and the way they’re transferring via the timber,” Dr. Hagelin stated. “So you may put a web in the best way and hope you’ll catch them that approach.”
Cross your fingers
Over the course of the five-year examine, the researchers managed to deploy 95 tags. They recovered 17 geolocator tags however simply 5 GPS tags — and three of the GPS tags failed, offering no information in any respect for causes the scientists nonetheless don’t perceive. “That was actually devastating,” Dr. Hagelin stated.
“However all was not misplaced,” she added. The geolocator information pointed to 13 vital stopover websites, from Washington to southern Peru, plus three major wintering areas in South America, the researchers reported in 2021. Tagging know-how has improved, so scientists with an urge for food for flycatcher catching might now concentrate on amassing extra detailed information on these places. “Am I the particular person to do it?” Dr. Hagelin stated. “Perhaps if I had the funding.”